What Is a Normal Aortic Valve Dimensionless Index?

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By Valerie Becker

The aortic valve dimensionless index is a metric used to assess the function of the aortic valve. This index is calculated by dividing the velocity time integral (VTI) of the left ventricular outflow tract (LVOT) by the VTI of the aortic valve. A normal aortic valve dimensionless index falls between 0.25 and 0.50.

Understanding Aortic Valve Function

The aortic valve is one of the four valves in the heart that regulates blood flow between different chambers of the heart and to different parts of the body. The aortic valve regulates blood flow from the left ventricle to the aorta, which then distributes oxygenated blood to various organs and tissues.

When functioning normally, the aortic valve opens fully during systole (when the heart contracts), allowing blood to pass through easily. During diastole (when the heart relaxes), it closes fully to prevent backflow into the left ventricle.

What Is Aortic Valve Stenosis?

Aortic valve stenosis occurs when there is narrowing or constriction in the opening of this valve, leading to obstruction of blood flow from the left ventricle into the aorta. This can cause symptoms such as chest pain, shortness of breath, and fainting spells.

Aortic valve stenosis can be diagnosed using echocardiography, which uses sound waves to create images of your heart. One metric used for diagnosis is measuring your aortic valve dimensionless index.

Calculating Aortic Valve Dimensionless Index

To calculate your aortic valve dimensionless index, your doctor will use echocardiography to measure two key parameters:

  • The VTI of your LVOT – this measures how fast blood flows through your LVOT during systole.
  • The VTI of your aortic valve – this measures how fast blood flows through your aortic valve during systole.

These two values are then used to calculate your aortic valve dimensionless index, which is obtained by dividing the VTI of the LVOT by the VTI of the aortic valve.

Normal Aortic Valve Dimensionless Index

A normal aortic valve dimensionless index falls between 0. A value below 0.25 indicates severe aortic stenosis, while a value above 0.50 indicates mild or no stenosis.

It’s important to note that your doctor will consider other factors as well when diagnosing aortic stenosis, such as the thickness of your heart muscle and the degree of calcification in your valve.

Conclusion

The aortic valve dimensionless index is an important metric used to assess the function of the aortic valve and diagnose conditions such as aortic stenosis. If you’re experiencing symptoms such as chest pain or shortness of breath, it’s important to speak with your doctor about getting an echocardiogram to assess your heart function and determine if there are any underlying issues affecting it.